Boom and pivotal jib structure



Feb. 28, 1967 P L C 3,306,468

BOOM AND PIVOTAL JIB STRUCTURE Filed Oct. 15, 1965 3 Sheets-Shet 1 INVENTOR. 55.4 /6 P0144 C/f Feb. 28, 1967 qp Lm 3,306,468

BOOM AND PIVOTAL JIB STRUCTURE Filed Oct. 15, 1965 I s Sheets-Sheet 2 a: n W

I\. I\ v Q o w g m g iv I INVENTOR. $54 /6 PULL/46h Feb. 28, 1967 s, POLLACK 3,306,468

BOOM AND PIVOTAL JIB STRUCTURE Filed 001;. 15, 1965 s sheets-sheet 5 4 INVENTOR. SEA/6 POZZflC/f mrrak/my United States Patent 3,306,468 BOOM AND PIVOTAL JIB STRUCTURE Selig Pollack, 11 W. 42nd St., New York, N.Y. 10036 Filed Oct. 15, 1965, Ser. No. 496,496 2 Claims. (Cl. 2l259) This invention relates to improvements in cranes of the type shown in United States Patents Nos. 3,034,661 of May 15, 1962, and No. 3,062,384 of November 6, 1962.

More particularly, this invention relates to a crane assembly having an adjustable beam jib. Still more particularly, this invention relate-s to an articulatable crane assembly which may include one or more booms, to which is pivotally connected an adjustably mounted jib, the assembly being characterized by the ability to set the jib at any predetermined angle with respect to the ground and to articulate the main boom, the jib maintaining said predetermined angle throughout all relative adjusted positions of the main boom.

More particularly, this invention relates to a rigging structure for a crane having a jib adjustably mounted there- 'to, the angle between the jib and the ground being adju-stableby actuation of powerized means on the crane chassis, the jib being enabled by the rigging structure employed to maintain the identical angular relationship to an improved crane structure.

'It is a further object of the invention to provide an improved crane structure embodying one or more relatively movable booms and a pivotally adjustably mounted jib.

A further object of the invention is the provision of a crane device which may incorporate two or more main links which are relatively adjustable and wherein the angular relationship of the upper link or links will remain constant with respect to the horizontal, notwithstanding pivotal movement of the lowermost chassis supported link or boom.

A further object of the invention is to provide a boom and pivotal jib structure wherein pivotal movement of the jib about the boom will not affect the moment arm of the jib.

To attain these objects and such further objects as may appear herein or be hereinafter pointed out, I make reference to the accompanying drawing, forming a part here- .of, in which:

FIGURE 1 is a schematic side elevational view of -21 crane device in accordance with the invention in various positions capable of being actuated by the parts;

FIGURE 2 is a detail view of the junction between the jib and boom, indicating specifics of the rigging;

FIGURE 3 is a fragmentary plan view of the section of the rigging of the jib indicated by the arrows 3-3 of FIGURE 2;

FIGURE 4 is a fragmentary plan View of the section of the rigging of the jib indicated by the arrows 44 of FIGURE 2;

FIGURE 5 is a fragmentary plan view of the section of the rigging of the jib and the jib quadrant indicated by the arrows 5-5 of FIGURE 2;

FIGURE 6 is a schematic view of an embodiment of the invention employing, in this instance, a main and an auxiliary boom in addition to the articulatable jib.

3,306,408 Patented Feb. 28, 1967 In accordance with the invention, there is provided a powerized crane 10 including a chassis 11 and a main boom 12, pivotally mounted to the chassis. There is rigidly secured to the chassis, a main quadrant 13 and an oppositely disposed prestressor quadrant 14, for purposes which will appear hereafter. The radii of the quadrants 13, 14 are disposed concentrically with respect to the pivot point of the boom 12.

A horizontally disposed trunnion 15 (see FIGURE 2) is supported at the upper end of the main boom 12, the trunnion 15 pivotal-1y supporting a second or auxiliary quadrant structure 16 comprising an upper quadrant member 17 disposed in parallelism with the quadrant 13, and a lower or prestressor quadrant 18.

The auxiliary quadrant structure .16 is maintained in parallelism with the lower quadrant by a quadrant tie 19 wrapped over and lying tangent to the lower quadrant, the lower end of said tie being made fast to the chassis and, in addition, wrapped'over the upper surface of the quadrant 17, the upper end of the tie 19 being made fast to anchor bracket 20 supported by the quadrant. While it is altogether possible to employ a single tie or fall 19, it is preferred, as best seen from FIGURE 5, that the tie or fall 19 comprise a pair of identical guy members.

As will be seen from said FIGURE 5, the quadrant 17 includes four side-by-side disposed grooves 21, 22, 23, 24. in the illustrated embodiment the ties 19 lying in the outermost grooves 21, 24.

For the purposes set forth particularly in United States Patent No. 3,062,384, a prestressor guy 25 is rigged under the upperand lower prestressor quadrants 18 and 14, re,- spectively, thus to prevent possible damage due to shock loading and possible reverse or counter-rotative movement of said jib, as fully set forth in said Patent No. 3,062,384. As the operation of the prestressor components is in no wise germane to the present invention, further description thereof is not deemed necessary.

Pivotally mounted about the trunnion 15, there is disposed an extended, articulat-able jib member 26. The jib member 26 preferably incorporates lateral, spacedapart brace portions 26a, 26b, linked together by suitable reinforcing struts. Similarly, mounted about the trunnion 15 are four independent sheaves 27, 28, 29 and 30.

From the description of the rigging of the upper quadrant 17, and in the manner set out in United States Patent No. 3,034,661, it will be appreciated that when the boom 12 is pivoted about its connection to the chassis,

the upper quadrant structure 16 will float or remain in the same angular relationship to the ground, i.e. it will rotate about the trunnion 15 in a manner to maintain it in parallelism with the lower quadrant 13 by reason of the wrapping and unwrapping action of the quadrant tie or ties 19.

The jib structure 26 which is mounted on the trunnion 15 may be independently articulated through the use of the jib control rigging next to be described.

The control rigging includes a pair of ties 31, which ties are wrapped over the inner grooves 22, 23 of the upper quadrant 17, the rearward ends of the ties being fixed to depending bracket members 32 formed on the undersurface of the quadrant 17. The forward end 31a of the ties or guys 31, as best seen in FIGURE 3, are made fast to a harness 33. The harness 33 rotatably carries a space-d pair of sheaves 34, 35. To the end 36 of the jib 26 there is pivotally mounted a -U brace 37, terminating in a laterally disposed strut or spreader 38. A pair of jib tie members 39, 39 have their ends fixedly supported to the spreader 38, the rearward ends 40, 40 of the tie members 39 being fixed to a harness 41 which is spaced from and disposed in opposition to the harness 33.

A pair of sheaves 42, 43 are rotatably mounted in the harness 41 in a spacing corresponding to the spacing of the sheaves 34, 35 of harness 33. A jib control cable 44 is rigged between the sheaves 34, 35 and 42, 43 and thence downwardly to the cab and lift engine maintained on the chassis, in a manner to cause the harnesses 33 and 41 to be shifted closer together or further apart, thereby to vary the angular relationship of the jib about the trunnion 15, respectively in an upward or downward direction.

This rigging is accomplished by the spaced legs 44a, 44b of the control cable 44, said legs being made fast to the harness 41 and then being led, respectively, under and then over the sheaves 35, 34, and then over and then under the sheaves 43, 42. The falls or cables 44a, 44b are thereafter led over the outer sheaves 30 and 27, respectively, which are mounted on trunnion 15, to a laterally extending equalizer (not shown) which functions, in the usual manner, to equalize the stress in the two lines. The equalizer is, in turn, connected to the crane lift engine through a further cable, it being readily understood that when the cable is slacked off, a clockwise rotation of the jib will be effected, since a greater spacing of the harnesses 33 and 41 will be permitted, whereas taking up on the cable connected to the lift engine will have a counter effect, namely, will result in the harness members 33 and 41 moving together and a counterclockwise or lifting rotation of the jib 26.

A main boom topping lift 45, which may be of single or double fall construction, is suitably rigged between the chassis 11 and an upper portion of the main boom 12 for controlling, in the usual manner, the angular position of the boom with respect to the chassis. Similarly connected to the engine by fall 46 is a lift hook 47, it being understood that, if desired, a track 48 may be secured to the under-surface of the jib so as to permit the use of a longitudinally movable trolley carriage in lieu of, or in addition to, the hook lift member.

From the foregoing description, the operation of the embodiment shown in FIGURE 1 will be apparent.

With the boom 12 positioned as shown in solid lines (FIGURE 1), the articulation of the boom will not affect the angular relationship of the jib. In this instance, in the position shown in dot and dash and labeled A, the boom 12 has been lowered from the solid line position through a desired angle. In the course of such movement, increments of the quadrant ties 19 have been wrapped over the lower quadrant 13 and comparable increments have been unwrapped from the upper quadrant 17, thus to effect the desired continued parallelism of the said quadrants. Since the jib is supported by ties wrapped over the quadrant 17, i.e. since the angular relationship of the jib with respect to the horizontal will be a function only of the length of the guy extending between the end 36 of the jib and overlying the quadrant 17, and since this length will not vary upon articulation of the main boom, the angle of the jib will not be affected by such articulation. It is, however, possible to vary the angle of the jib with respect to the horizontal by merely shortening to distance between the harnesses 33 and 41 by drawing in the jib control cables 44. The B position as shown in FIGURE 1 illustrates the movement from the solid line position which results from taking up on cables 44.

In the C position shown in FIGURE 1, the boom 12 has been lowered from the B position to a fully horizontal position, whereupon it will be seen that the angular relationship of the jib with respect to the ground has remained constant in shifting from the B to the C position.

The D position of FIGURE 1 may be reached either by articulating the boom from the A position to a horizontal position or by causing the jib to be lowered from the C position by slacking out on the falls or cables 44.

From the foregoing it will be evident that an almost infinite variety of positions may be achieved by properly maneuvering the boom and jib controls.

It is an important feature of the invention that the load resisting force moment arm of the jib about the boom remain a constant throughout all articulated positions of the jib with respect to the horizontal. This result inheres in the illustrated structure since the jib supporting guys 31 at all times are tangentially engaged over the upper quadrant 17. Thus, notwithstanding the articulated position of the jib about the trunnion 15, the resistive or load supporting moment is at all times defined by the spacing between the radius of the trunnion 15 and the point of tangency of the cables 31 over the quadrant 17. This distance or moment arm will, of course, be at all times a constant.

The load carrying capacity of the jib will, of course, vary in accordance with the angle between the jib and the horizontal it being readily recognized that the moment or torque arm which opposes the resistance moment arm previously described will be a function of the rotative position of the jib. Thus, if the jib is disposed in a substantially vertical position, a considerably greater lifting force may be exerted, since the lifting force will be applied through a short moment arm defined by the horizontal displacement of the load lifting fall from the trunnion 15. correspondingly, when the jib is disposed horizontally, the weight will be applied to the jib through the greatest possible moment arm and, thus, the lifting capacity will be most restricted in this position.

A great advantage of my invention lies in the facility of computing the lifting stresses of the component members in the jib structure in the field. Since, as above noted, the force resistive moment arm is a constant, the load moment determined by the product of the load by the horizontal displacement, both known factors, when divided by this constant, give the strain on the topping life directly and the jib indirectly or, vice-versa, knowing the allowable strain on jib and topping lift, the allowable load and horizontal displacement can thus be readily determined. The simplicity of calculating the force components under such circumstances is to be contrasted with prior jib structures wherein, upon articulation of the jib, the resistive moment arm varies radically and in a manner not subject to measurement with any degree of exactitude, making the calculation of the stresses in all component members difiicult and hazardous.

In FIGURE 6 there is shown an embodiment of invention wherein there is included a main boom 100, pivotally supporting an auxiliary boom 101, which boom in turn supports an articulatable jib 102. In this construction, the principles of operation are identical with the device previously described.

There is, in the embodiment of FIGURE 6, a lower quadrant 103, an intermediate quadrant 104, and an upper quadrant 105, the intermediate and upper quadrants 104, 105, respectively, being mounted so that their radii are coaxilly disposed with respect to the pivot point between the booms 101 and 100, and the jib and boom 102, 101, respectively.

In this case, a guy 106 is wrapped over the lower and intermednate quadrants 103, 104, respectively, to keep these quadrants in parallelism through all movement of the boom 100.

Similarly, guy 107 is wrapped over the quadrants 104, 105, to maintain the latter mentioned quadrants in parallelism, notwithstanding any relative movement between the auxiliary boom 101 and the main boom 100.

The jib 102 is pivotally mounted with respect to the auxiliary boom 101, including a shortenable tie 108 which is led to the hoisting engine of the crane, the tie 108 being connected adjacent the end of the jib 102 and being wrapped over the quadrant 105. It will be understood that the shortening of the tie 108 may articulate the jib angularly in a vertical plane, in the manner described in connection with the embodiment of FIG- URE 1. In a similar manner, the boom 101 may be articulated with respect to the boom 100.

To accomplish this end, a tie 109 is fixed to the end of auxiliary boom 101 and is wrapped over quadrant 104, provision being made to shorten the effective length of this tie between the quadrant and boom end, thus to enable an articulation of the auxiliary boom about the main boom. Any suitable means for shortening this connection may be employed, as is the case with the connection between the jib and uppermost quadrants in both embodiments.

As in the prior described embodiment, a main boom topping lift 110 is provided, to permit the usual articulation of the main boom 100 about the chassis.

From the foregoing description of the embodiment of FIGURE 6, it will be evident that the jib may be shifted from the solid line position to the position E by shortening the lift or cable 108. By thereafter articulating the main boom 100, shifting it to a downward position through a slacking off of the topping lift 110, the components may be disposed in the position shown in FIG- URE F.

Again, by slacking off on the cable 109 controlling auxiliary beam 101, the device may be further altered to position G.

Finally, the jib may be lowered, leaving the device in position H by slacking off on jib control cables 108. Obviously the device may be erected beginning with position H by reversing the order of steps.

From the foregoing it will be readily recognized that by using the novel principles employing one or more floating quadrants, an extremely versatile crane construction may be provided. The construction may be made even more versatile by using a plurality of booms and floating quadrants, the resultant crane structure being capable of adjustment so as to reach over or around buildings in the most efficient manner possible. Thus, the structure of the present device will accomplish all of the ends set forth in the said prior patented devices and will provide even greater flexibility.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is:

1. An infinitely variable multi-boom crane structure having an adjustable jib comprising:

(a) achassis;

(b) a main boom pivotally mounted on said chassis for retraction and reach;

(c) an auxiliary boom having an end pivotally mounted to the free end of said main boom and having a free end;

(d) a jib pivotally mounted to the free end of said auxiliary boom;

(e) a fixed quadrant mounted on said chassis,

(f) first and second auxiliary quadrants of radius equal to said fixed quadrant pivotally mounted at the free ends, respectively, of said main boom and said auxiliary boom, the axes of said auxiliary quadrants being coincident, respectively, with the pivotal connections between said main and auxiliary booms and said auxiliary boom and said jib,

(g) a flexible guy wrapped over said fixed quadrant and the auxiliary quadrant at the free end of said main boom, and tangentially engaging both said quadrants throughout all pivoted positions of said boom,

(h) a flexible guy wrapped over said auxiliary quadrants and tangentially engaging said quadrants throughout all pivoted positions of said auxiliary boom,

(i) I auxiliary boom adjustment means for controlling the angular relation of said main and auxiliary booms comprising a flexible topping lift wrapped over said first auxiliary quadrant and extending to a point adjacent the free end of said auxiliary boom,

(j) jib adjustment means for controlling the angular relation of said job and auxiliary boom comprising a second flexible topping lift wrapped over said second auxiliary quadrant and extending to a point adjacent the free end of said jib, and

(k) means for varying the length of said first and second topping lifts, thereby to articulate said auxiliary boom with respect to said main boom and said jib with respect to said auxiliary boom.

2. A device in accordance with claim 1 and including prestressor quadrants of equal radius mounted, respectively, in opposition to and coaxially with said fixed first and second quadrants, each said prestressor quadrant being connected to the next adjacent prestressor quadrant by a flexible tensioning guy member Wrapped under and tangentially engaging the surfaces of said prestressor quadrants.

References Cited by the Examiner UNITED STATES PATENTS 3,034,661 5/1962 Pollack et a1. 212 -59 3,037,641 6/1962 Potter et a1 2l2144 3,062,384 11/1962 Pollack 2l2-144 ANDRES H. NIELSEN, Primary Examiner. 

1. AN INFINITELY VARIABLE MULTI-BOOM CRANE STRUCTURE HAVING AN ADJUSTABLE JIB COMPRISING: (A) A CHASSIS; (B) A MAIN BOOM PIVOTALLY MOUNTED ON SAID CHASSIS FOR RETRACTION AND REACH; (C) AN AUXILIARY BOOM HAVING AN END PIVOTALLY MOUNTED TO THE FREE END OF SAID MAIN BOOM AND HAVING A FREE END; (D) A JIB PIVOTALLY MOUNTED TO THE FREE END OF SAID AUXILIARY BOOM; (E) A FIXED QUADRANT MOUNTED ON SAID CHASSIS, (F) FIRST AND SECOND AUXILIARY QUADRANTS OF RADIUS EQUAL TO SAID FIXED QUADRANT PIVOTALLY MOUNTED AT THE FREE ENDS, RESPECTIVELY, OF SAID MAIN BOOM AND SAID AUXILIARY BOOM, THE AXES OF SAID AUXILIARY QUADRANTS BEING COINCIDENT, RESPECTIVELY, WITH THE PIVOTAL CONNECTIONS BETWEEN SAID MAIN AND AUXILIARY BOOMS AND SAID AUXILIARY BOOM AND SAID JIB, (G) A FLEXIBLE GUY WRAPPED OVER SAID FIXED QUADRANT AND THE AUXILIARY QUADRANT AT THE FREE END OF SAID MAIN BOOM, AND TANGENTIALLY ENGAGING BOTH SAID QUADRANTS THROUGHOUT ALL PIVOTED POSITIONS OF SAID BOOM, (H) A FLEXIBLE GUY WRAPPED OVER SAID AUXILIARY QUADRANTS AND TANGENTIALLY ENGAGING SAID QUADRANTS THROUGHOUT ALL PIVOTED POSITIONS OF SAID AUXILIARY BOOM, (I) AUXILIARY BOOM ADJUSTMENT MEANS FOR CONTROLLING THE ANGULAR RELATION OF SAID MAIN AND AUXILIARY BOOMS COMPRISING A FLEXIBLE TOPPING LIFT WRAPPED OVER SAID FIRST AUXILIARY QUADRANT AND EXTENDING TO A POINT ADJACENT THE FREE END OF SAID AUXILIARY BOOM, (J) JIB ADJUSTMENT MEANS FOR CONTROLLING THE ANGULAR RELATION OF SAID JOB AND AUXILIARY BOOM COMPRISING A SECOND FLEXIBLE TOPPING LIFT WRAPPED OVER SAID SECOND AUXILIARY QUADRANT AND EXTENDING TO A POINT ADJACENT THE FREE END OF SAID JIB, AND (K) MEANS FOR VARYING THE LENGTH OF SAID FIRST AND SECOND TOPPING LIFTS, THEREBY TO ARTICULATE SAID AUXILIARY BOOM WITH RESPECT TO SAID MAIN BOOM AND SAID JIB WITH RESPECT TO SAID AUXILIARY BOOM. 